Process of making sulfuric acid and electrolytic iron.



A. s. RAMAGB. PROCESS OF MAKING SULFURIG ACID AND ELECTROLYTIC IRON. APPLIOATIQN FILED JAN. 9, 1909. RENEWED JULY 14, 1910.

984,703, I Patented Feb. 21, 1911.

w zewewr."

m Q WML W 'wfef' a.

UNITED STATES, PATENT OFFICE.

ALEXANDEE S. RAMAGE, OF DETROIT, MICHIGAN, ASSIGNOR, BY ME SNE ASSIGNMENTS, I

TO NATIONAL TUBE COMPANY, OF PITTSBURG, PENNSYLVANIA, A CORPORATION or NEW JERSEY.

Pno'cEssor MAKING SULFURIC ACID AND ELECTROLYTIC men.

Specification of Letters Patent.

Patented Feb. 21, 1911.

Application filed January 9, 1969, Serial No. 471,526. Renewed July 14, 1910. Serial No. 572,020.

To all whom "it may concern:

Be it known that I, ALEXANDER S. RAM- AGE, a citizen of the United States, residing at Detroit, in the county of -Wayne and State of Michigan, have' invented certain new and useful Improvements in Processes of Making Sulfuric Acid and Electrolytic Iron, of which the following is a specification.

This invention relates to the production of electrolytic iron from ferric ores, with the coincident production of sulfuric acid.

According to the invention a ferric solution obtained by treating a suitable ore of iron-with sulfuric acid is first reduced to the ferrous state, and is then subjected 'to electrolysis with insoluble anodes, the anode being depolarized during the electrolysis by means of dissolved sulfur dioxid.

In practicing the process it is necessarythat means should be provided for prevent ing admixture of the positive electrolyte containing dissolved sulfur diox'id with the electrolyte surrounding the cathodes; for if such admixture should occur a reduction of sulfur dioxid would take place in the region of the cathode resulting in the contamination of the metallic iron. This reduction of sulfur dioxid is primarily due to the fact that when the acid liquor from the anode compartment is permitted to flow to the region of the cathode there occurs a considerable evolution of hydrogen by which the sulfur dioxid is quickly reduced, Moreoperation. By (the use of adiaphragm over, the, acid liberated at the anodes or there produced by the oxidation of the sulfur dioxid, is distributed throughout the electrolyte, and redissolves the deposited iron "at a progressively increasing rate, thereby greatly reducing the efficiency of the or equivalent means for preventing admixture of the positive and negative electrolytes, the cathode compartment is readily maintained free or substantially free from sulfur dioxid and sulfuric acid.

- .I prefer to proceed substantially as follows: Aferric one, as for example hematite,

- is dissolved in sulfuric acid, the solution being preferably aided by heat and by the fine division of the ore, with agitation if necessary. Theresulting ferric solution is then reduced to the ferrous state,preferably by meansof sulfur dioxid, conveniently supplied in the form of gases from pyrites or sulfur burners. This ferrous solution is then supplied in separate streams to the anode and cathode compartments of a suitable electrolytic cell, thatportion of the solution flowing to the positive compartment of the cellcontaining an excess of sulfur dioxid and being preferably saturated with the gas. The portion of the electrolyte flowing to the negative compartment is on the other hand substantially free from the dissolved gas.

For a, full understanding of the invention reference is made to the accompanying drawing, in which Figure 1 is a diagrammatic plan view of a' suitable arrangement of saturating apparatus, and Fig. 2 is a horizontal section of the electrolytic cell on a relatively large scale.

In said drawing 1 represents a solution tank, tower or apparatus of any desired type, wherein the ore is subjected to the action of' a suitable solvent liquid. The sol vent liquid may consist initially of sulfuric acid, anv acid pickle liquor, or other liquid containing sulfuric acid, but in the after stages of the process will preferably consist of the acid liquor flowing from the electrolytic cells, or a portion thereof, as hereinafter described. From the solution apparatus 1 the liquid containing ferric sulfate flows to a suitable tower or scrubber 2-, wherein it is substantially reduced to the ferrous state by sulfur dioxid introduced through the. pipe 11 from pyrites or sulfur burners. From the tower 2, a portion of the liquor flows through conduit 3 to a tank 4 ,.wherein any excess of sulfur dioxid may be removed, as'for example by the careful addition of ferric sulfate solution. The ferrous sulfatesolution then flows through eonduit 5 to the negative compartments of the 'electrolytic'cell 7. A like volume of liquor flows from the tower 2 through conduit 6 'to a-second tower or scrubber 8, wherein it is treated with sulfur dioxid supplied through pipe 9, being preferably fully impregnated or saturatedwith thegas. This impregnated liquor then flows through conduit 10 to the positivecompartments of the electrolytic cell.

The electrolytic cell may be of any desired type, that illustrated comprising a ser1es of abuttingwooden frames 12 between WlllCll are clamped asbestos diaphragms 13. Each frame contains an electrode, the anodes 14 being preferably of lead, and the cathodes 15 consisting usually of iron; The anodes and cathodes are disposed in alternate frames, and passages are so'arrangcd in the frame walls that the impregnated liquor may be caused to flow, through passages 1 6, through the several anode compartments 111 succession, while the unimpregnated liquor flows through similar passages 17 to the several cathodecompartments.

It will be observed that the arrangement of the several compartments of the cell, and of the intermediate passages, is such that the anode and cathode liquors on opposite sides of the several diaphragms flow always in the same direction with respect to each other; that is to say, the flow is relatively.

uni-directional. This arrangement has been found in practice to be highly effective in avoiding undue diffusion between the several compartments in cases where porous diaphragms of low resistance and high permeability are employed. Preferab y the effluent liquors from both anode and cathode compartments are united in a common receiving tank 18, from ,which theytare removed for utilization.

It will be understood that any number of electrolytic cells may be used in series or in multiple, the best results being obtained by removing a portion onlyvof the iron and maintaining the liquor in continuous circulation through the solution apparatus and the electrolytic cells. By proceeding in this manner the operations of solution and electro-deposition are rendered regular in character, and the operation proceeds with the minimum of attention. The fall of potential in individual cells is usually from 1% to 2 volts, the current density varying according to the character of deposit required from 30 to 100 amperes per square foot. A temperature between 100 and 120,? Fahrenheit is preferred. Thereduction of the ferric solution b sulfur dioxid yields a large amount of sol furic acid, as per the following equation:

F 2( 4)s+ 2+ 2 ,2FeSO,+2H,SO,. A further quantity of acid is produced during the elect-rolytic'operation by' oxidation in the region of the anode of the dis solved sulfur dioxid. The liquor floyi ing from the cells contains therefore a large excess ofsulfuric acidand I refer -to concentrate this liquor, or a ort1on of the same,

and tof'odistil. sulfuric acid therefrom, where by the acid is directly recovered in ma rket I able form. The residual liquor, after such dilution as may be required, is returned to the solution apparatus, for re-use m the process, which is therefore cyclical in charpositive and negative electrolytes, and de-" polarizing the anode by sulfur'dioxid while maintaining the electrolyte in the region of the cathode substantially free from sulfur dioxid.

2. The process of making sulfuric acid and electrolytic iron, which consists in dissolving a ferric ore in sulfuric acid, reduc ing the ferric sulfate, to ferrous sulfate by sulfur dioxid, electrolyzing the resulting ferrous solution in an electrolytic cell provided with a diaphragm and an insoluble anode, and depolarizing the anode by sulfur dioxid while maintaining the electrolyte in the region of the cathode substantially free from sulfur dioxid.

3. The process of producing-sulfuric acid and electrolytic iron, which consists'in dissolving a ferric ore in sulfuric acid, reducin the ferric sulfate to ferrous sulfate by su ful dioxid, electrolyzing the resulting ferrous sulfate solution in an electrolytic cell provided with an insoluble anode and with means for preventing admixture of the positive and-negative electrolytes, depolarizing the anode by sulfur dioxid, separating su furic acid from the electrolyte, and employin the residual acidliquor for the solution 0 aferric ore.

4:. The process of making sulfuric acid and electrolytic iron, which consists in dis-. solving a ferric ore in sulfuric acid, reducing the ferric sulfate to ferrous sulfate by sulfur dioxid, electrolyzing the resulting ferrous solution in an electrolytic cell'pro solving a ferric'ote in-sglfuric acid, reducing sa mos :3

the ferric sulfate to ferrous sulfate by sulfur of said diaphragms, and depolarizing the dioxid, electrolyzing the resulting ferrous anodes by sulfur dioxid. 10 I solution by passing the same successively in In testimony whereof, I aifix my signature proximity to aplurality of cathodes in an in presence of two-witnesses.

electrolytic cell provided with diaphragms A ALEXANDER S. RAMAGE. and insoluble anodes, maintaining a rela- Witnesses: tively uni-directional flow of the positive VIDA M. SMITH,

and negative electrolytes on opposite sides 0. P. TOWNSEND. 

